Hull's Minesweepers

During the First World War, 300 Hull ships were used as minesweepers and for searching submarines. Hull lost 61 of these Minesweeping trawlers on Admiralty service during the war. On average half the crew of a minesweeper were lost with the ship. By the end of the War, only 91 Hull owned ships were afloat, 9 of which had been built during the war. Hull lost nearly 1,200 merchant crewmen, another 267 Royal Navy sailors and 38 Royal Marines.The majority of these died at sea and have no known grave. To add to the tragedy, there was little compensation for a sailor's family. Sailors' pay stopped when their ship sank, and usually only paid if they died with the ship. Sailors who left their ship in life boats were deemed to have discharged themselves from duty and often had their sea pay docked.

Dangerous work for fishing trawlers used as minesweepers

When the Royal Naval Reserve (RNR) was first created in 1859, it consisted of up to 30,000 merchant seamen and fisherman who the Navy could call on in times of crisis.Fishing trawlers were strong, sturdy ships, designed to withstand severe weather conditions out at sea, and in 1907 the Commander-in-Chief of the Home Fleet, Admiral Lord Beresford, recognised that trawlers could be used as minesweepers. His recommendation led to the formation of the Royal Naval Reserve (Trawler Section) in 1910, with approval to mobilise 100 trawlers during any crisis period and enrol 1,000 men to man them.

It also introduced a new rank, that of 'Skipper' RNR, into the Navy List. By the end of 1911, 53 skippers had joined. In 1912 a further 25 enrolled and the Trawler Section of the Royal Naval Reserve, consisted of 142 trawlers manned by 1,279 personnel. 31 more skippers joined before the war started in August 1914, making a total of 109 skippers. Another 315 more volunteered by the end of the first week in October. By the end of 1915 the Minesweeping Service employed 7,888 officers and men.

The Royal Naval Reserve (Trawler Section):

Before the war started there were already 142 trawlers in the Trawler Section of the RNR and 109 skippers enrolled. During the first week of the war in 1914, 94 trawlers were allocated for minesweeping duties and dispersed to priority areas, including Cromarty, the Firth of Forth, the Tyne, the Humber, Harwich, Sheerness, Dover, Portsmouth, Portland and Plymouth.

They were supplied with mine gear, rifles, uniforms and pay as the first minesweepers.They were commanded by naval officers, some from the retired list, who had received a brief training in minesweeping. Apart from the skippers, officers were also required to supplement the handful of naval officers of the existing minesweeping service. Most of the trained pre-war RNR and RNVR officers had already been called up for service in the Fleet. For the new minesweeping and auxiliary patrol flotillas, officers and civilians were obtained from the Merchant Navy and given temporary commissions in the RNR and RNVR. To bolster naval discipline, various Royal Fleet Reserve and pensioner petty officers were distributed among the vessels.

In August 1914 the Royal Navy began to requisition more trawlers and adapt them for minesweeping duties, fitting them out with heavy guns, machine guns and depth charges. By the end of 1916 the Navy had requisitioned so many trawlers, and the war had such an impact on shipping, that the supply of fish to the UK was severely limited. New trawlers were also built. Between 1914 and 1918, 371 trawlers were built in the Humber shipyards and almost all of them were taken up by the Navy and used as minesweepers, submarine spotters and coastal patrol boats. Men were asked to volunteer for the new service, and many did so. The Humber area provided over 880 vessels and 9,000 men from the fishing industry to support the war effort.

What are mines?

A mine is an explosive device left in the water to explode on contact with a ship or submarine. Mines were difficult to see and very effective once they had struck a target. The minesweepers had to ‘sweep’ the mines using wires, bring them to the surface then detonate them by firing on them. Moored mines only had a short length of chain shackled to them. The rest of the mooring was wire cable or even sisal rope in some cases; otherwise the mine could not support the weight of its mooring, particularly in deep water. This was the part of the mooring, that the sweep wire or any fitted cutter, was intended to sever. Sometimes gathering a group of mines together could lead to multiple explosions. A chain reaction could result in one massive detonation which would often sink the minesweeper. Minesweeping was therefore extremely dangerous work. It required 'nerve, skill and unremitting watchfulness', according to a journalist at the time.

How did they 'sweep' mines?

Early mine sweeps simply comprised of chains towed over the seabed between two ships, or even by a single ship to drag mines and their moorings out of a channel. These were later replaced with serrated wire cables towed between two ships (Actaeon Sweep). Development of the Oropesa Sweep, with its divertors and depth-keeping kite, allowed sweeps to be towed by a single ship. Sweep wires were made from flexible, steel wire rope and streamed from each quarter of a minesweeper.

Postwar mine-clearing:The cables were laid right or left-handed according to the side streamed. This helped the wires achieve hydrodynamic lift and spread. A single strand in each wire was laid in the opposite direction to provide a serrated cutting effect. The 'Paravane', a form of towed underwater "glider", was developed from 1914–16 by Commander Usborne and LieutenantC. Dennistoun Burney, funded by Sir George White, founder of the Bristol Aeroplane Company. Initially developed to destroy naval mines, the paravane would be strung out and streamed alongside the towing ship, normally from the bow.The wings of the paravane would tend to force the body away from the towing ship, placing a lateral tension on the towing wire. If the tow cable snagged the cable anchoring a mine then the anchoring cable would be cut, allowing the mine to float to the surface where it could be destroyed by gunfire. If the anchor cable would not part, the mine and the paravane would be brought together and the mine would explode harmlessly against the paravane. The cable could then be retrieved and a replacement paravane fitted. Burney explosive paravanes were deployed from torpedo boat destroyers in a configuration known as the 'High Speed Sweep' to counter submarines. However, most paravanes were non-explosive and were streamed by larger warships and merchant ships as self-defence measures to divert moored mines away from their hulls. They comprised a wire streamed to each side from the bows with a float secured to the end to divert it outwards

At the end of the war, Britain was one of 26 countries represented on an International Mine Clearance Committee dedicated to clearing 40,000 square miles of sea of leftover mines. Several hundred thousand mines had been laid during the conflict by both sides. Each power was allotted an area to clear. The Mine Clearance Service was formed in 1919 and worked to clear Britain’s allocated area until it was disbanded the following year. By the time of the Armistice, the Trawler Reserve now consisted of 39,000 officers and men of whom 10,000 were employed in minesweepers and the rest in the auxiliary patrol. The 10 ex-torpedo gunboats available as minesweepers at the outbreak of the war had been replaced by purpose-built ships, including:

Illustrations of life on board a trawler - "In the Wheelhouse, Mail Day, playing cards, cleaning guns, the Galley cook, the stoker, the radio officer,slipping the "kite" which controls the mine sweeping depth."